In many spray applications in which a liquid under pressure is forced through an orifice of a spray tip assembly, the spray tip assembly is adapted to permit the substitution of different orifice members in order to vary the spray pattern. In many cases the spray tip assembly is supplied with orifices of varying sizes. As an aid for cleaning the spray tip, many spray tips assemblies include a rotatable turret member which carries the orifice member and which can be rotated within a central body to reverse the orifice for cleaning.
In U.S. Pat. No. 3,831,862 a spray tip assembly is disclosed in which the spray tip orifice is mounted in a removable and reversible sleeve which is secured in the housing with a sliding pin interlock that seats against a spring biased seal.
In U.S. Pat. No. 4,116,396 a spray tip assembly is disclosed in which the spray tip orifice is mounted in a cylindrical turret member which can be rotated in the housing to reverse the orifice member for cleaning.
U.S. Pat. No. 4,165,836 discloses a similar type spray tip including a reversible orifice and teaches that the solid plastic seal which seals the rotatable member carrying the orifice exhibits excessive wear and suggests that an entirely metal seal be used to provide metal-to-metal contact between the seal and the turret member.
In a similar vein, U.S. Pat. No. 4,483,481 discloses a spray tip assembly which provides a seal construction to overcome the prior art difficulties with solid plastic seals by providing a metal seal having a thin plastic between the metal sealing member and the turret member.
U.S. Pat. No. 4,635,850 discloses a spray nozzle including a central body, an adaptor for attachment to a spray gun, safety tip attached to the front of the central body. A rotatable cylinder is rotatably mounted in the central body and carries the nozzle and orifice which can be reversed by rotating the cylindrical body. A separate sealing joint comprises several pieces placed between the diffuser of the spray gun and extends through the central body to seal the rotatable cylinder.
The design of the spray tips of the type illustrated in the foregoing U.S. patents contain a substantial number of parts which add to the expense of the manufacture of the spray tip. Consequently, the cost of such spray tips is relatively high and spray tips having replaceable orifices are primarily designed for commercial users who require a variety of orifice sizes and to whom the cost of the spray tips is not a major concern. However. airless spraying is a technique that is becoming increasingly popular for non-commercial uses around the home where interchangability of orifices is not a major concern but where the cost of the spray tip is a factor.
Accordingly it would be desirable to provide a low-cost simple spray tip for airless spraying which has the convenience of the reversible orifice for cleaning but which is economical to manufacture and can be sold at retail at a relatively low cost. In addition it would be desirable to have such a spray tip which can be disposed of when the job is finished.